Number of the records: 1
Early post-embryonic development in .i.Ellipsostrenua./i. (Trilobita, Cambrian, Sweden) and the developmental patterns in Ellipsocephaloidea
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SYSNO ASEP 0499752 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Early post-embryonic development in Ellipsostrenua (Trilobita, Cambrian, Sweden) and the developmental patterns in Ellipsocephaloidea Author(s) Laibl, Lukáš (GLU-S) RID, ORCID, SAI
Cederström, P. (SE)
Ahlberg, P. (SE)Source Title Journal of Paleontology. - : Cambridge University Press - ISSN 0022-3360
Roč. 92, č. 6 (2018), s. 1018-1027Number of pages 20 s. Publication form Print - P Language eng - English Country US - United States Keywords systematic position ; series 2 ; ontogeny ; larvae ; reconstructions ; biostratigraphy ; morphology ; phylogeny ; evolution ; China Subject RIV DB - Geology ; Mineralogy OECD category Paleontology Institutional support GLU-S - RVO:67985831 UT WOS 000449392500005 EID SCOPUS 85055223143 DOI 10.1017/jpa.2018.25 Annotation This study documents the early post-embryonic developmental stages (protaspides and early meraspides) of the Cambrian trilobite Ellipsostrenua granulosa (Ahlberg, 1984) from the Gardsjon Formation of Jamtland, Sweden. The early protaspid stage is characterized by a circular outline of the exoskeleton, two pairs of fixigenal spines, a short preglabellar field, a genal swelling, and prominent bacullae. The late protaspid stage differs only in having the trunk portion discernible. Early meraspid cranidia are sub-rectangular with prominent palpebral lobes, a wide anterior margin, a proportionally long anterior branch of the facial suture, and intergenal spines. Meraspid pygidia tentatively assigned to this species possess comparatively long macrospines. Small hypostomes associated with E. granulosa bear at least four pairs of marginal spines. A comparison of the early developmental stages of E. granulosa with some other species of Ellipsocephalidae and with species of the closely related Estaingiidae reveals several similarities. The conservative morphology of the early protaspid stage with only two pairs of fix igenal spines, the timing of the development of the trunk portion, and the presence of genal swellings and prominent bacullae could be phylogenetically informative. The range of size variation of the early protaspid stages in two families may be related either to taxonomical differences between Ellipsocephalidae and Estaingiidae, or to environmental differences in various paleogeographic settings. Workplace Institute of Geology Contact Jana Popelková, popelkova@gli.cas.cz, Sabina Janíčková, Tel.: 233 087 272 Year of Publishing 2019
Number of the records: 1